Soft paw sensor for tactile and force sensing in legged robots

Abstract

The adaptability of legged robots to uneven terrain and their minimal ground impact have driven significant research advancements, establishing them as ideal solutions for complex and delicate environments. Tactile sensing and environmental perception are critical for enhancing robot performance, as they are essential for maintaining dynamic balance and achieving precise control. This paper presents a novel soft contact and force sensor designed for quadrupedal robot legs’ pads (end effectors). The innovative soft sensitive paw, made from flexible conductive membranes, simultaneously measures force and contact point position, enabling environmentally aware decision-making and supporting proprioceptive awareness. Experimental tests demonstrate its soft, spherical design provides excellent adaptability and grip on various terrains. Its sensing surface covers 83.3% of the sphere’s area, with a measurement error of only 0.14%. This capability allows the sensitive paw to detect ground contact as well as lateral and upper leg interactions, offering a robust and versatile tool for navigation and operation in complex environments. To validate its performance, the sensor was tested using custom-built test benches and subsequently mounted on the Lupoh quadruped robot, which was developed in our laboratory for further evaluation.